When it comes to laying concrete, nothing can weaken its stability more than air bubbles which become trapped and aren’t smoothed out.

This is where concrete vibration comes in to solve this common problem throughout the construction industry.

While there are numerous variations of concrete vibration, this building code requirement is vital to laying a solid concrete foundation.

To learn more about the most essential concrete vibrator techniques and how to master the art of laying smooth concrete, just keep on reading.

Understanding Concrete Vibrator Basics

When concrete is mixed and poured, the inevitable result is a concrete mixture which contains thousands of air bubbles.

Any solid or weight-bearing structure would be compromised by having a concrete foundation riddled with air bubbles.

The solution to this tricky construction conundrum? Concrete vibrations which vigorously shake the poured concrete until these air bubbles disappear.

Also known as concrete consolidation, this process in any building project is mandatory according to the Building Code of Australia (BCA).

This being said, the laying of concrete and its consolidation requires a good amount of planning.

Here are a few essential items to keep in mind for your next concrete vibration project:

• The ideal mixture of concrete aggregate
• Accurate measurements of concrete slump before it sets
• Tightly sealed forms to prevent leakage
• A reliable and easily accessible power source
• An adequate number of concrete vibrators
• Sufficient time set aside for concrete vibration
• Sufficient manpower for the concrete laying and vibration project
• Backup equipment in case of equipment failure

It’s important to go into every concrete pouring and consolidation job with these items checked off your list.

Variations of Concrete Vibration

Throughout the construction industry there are three variations of concrete vibration:

1. Formwork

Recommended for precast concrete work, this form of vibration uses external electric or air-driven concrete vibrators.

They are usually mounted to the exterior formwork and are ideal for larger pours of concrete. External vibrators are usually placed 15 centimetres apart.

2. Surface

This form of concrete vibration works best on concrete pours which are no deeper than 15 centimetres (6 inches). Large concrete vibrators, known as jumpers, are typically used for this type of project.

The vibrators are directed manually across the surface of a concrete slab and are ideal for creating a smooth, aesthetically pleasing finish.

3. Internal

This is the most commonly used form of concrete vibration throughout the industry. These types of concrete vibrators are handled by a single operator and are electric or pneumatically driven.

The process is relatively simple; the worker jams the vibrator down into the concrete, slowly withdrawing it to remove all air pockets.

Timing Requirements

Throughout the construction industry, the process of concrete vibration tends to be rushed due to impending deadlines.

However, this is a process which requires time well spent and plenty of attention in order to secure a solid foundation of concrete.

If using an internal concrete vibration technique, the rule-of-thumb is to withdraw the vibrator slowly from the concrete. This is generally at a rate of 2.5 centimetres per second.

If bubbles still emerge as the concrete vibrator is withdrawn, the area still requires vibration.

On the other hand, it’s also important to avoid holding the vibrator in the concrete too long as the water and aggregates will separate.

This can compromise the overall structure and aesthetics of the concrete.

Choosing the Best Concrete Vibrator For the Job

This largely depends on the type of concrete mixture you’re working with on a construction project.

Generally, high frequency, low amplitude vibrators work best for high mortar concrete mixes. While low frequency, high amplitude vibrators work best for stiff concrete.

It’s important to choose the best type of vibration style as well as the ideal frequency and amplitude of your vibrator to achieve the best outcome.

Essential Vibration Techniques to Remember

In order to achieve the best possible outcome on a concrete pouring project, these essential vibration techniques should help you out:

• Always remember to have a spare concrete vibrator or two, depending on the size of the project
• Keep in mind that low slump (stiffer) concrete will always require more vibration time
• Some concrete forms are self-consolidating, meaning they require no vibration treatment
• Always ensure your concrete vibration penetrates through to previous layers of pre-poured concrete (at least 15 centimetres)
• Always insert your concrete vibrator as close to the vertical as possible to maximize its effect
• If you over-bend or over-extend the vibrator there’s a chance it will fail
• Avoid being tempted to use the vibrator as a concrete placement tool, causing the concrete surface to become uneven
• Each concrete vibration should be at least 10 seconds in length
• Remember to withdraw the vibrator from the concrete at a rate of 2 centimetres per second
• Always ensure the vibrator is fully submerged into the concrete for maximum effect
• Always ensure the radius of action of the vibrator is four times the size of the vibrator tip diameter
• When air no longer escapes from the concrete during vibration, you know the area has been vibrated sufficiently
• Avoid turning on the concrete vibrator before it’s properly submerged in the concrete
• Never force a vibrator down into concrete as it could come into contact with steel rebar and be damaged
• You’ll know it’s time to stop vibration when the concrete begins to take on a sheen
• Always double-check the concrete area hasn’t been previously vibrated by co-workers before starting on a job

Looking for High-Quality Tradesman Tools?

If you’re in the construction industry and on the hunt for a top quality concrete vibrator, rest assured Canberra Diamond Blade supplies it.

Save yourself time and money when looking for the best trade tools for the job by shopping at our online store.

We offer tools and machinery for bricklayers, concreters and specialty cutting and grinding applications.

Looking for something very specific? Don’t hesitate to give us a call.